DRG Coding Advisor-Stimulation therapy has many faces, but few codes

Question: Our clinic provides several types of stimulation therapy, including electrical nerve stimulation, osteogenic stimulation, and neuromuscular electrical stimulation. What CPT codes are used for these procedures, and are they covered by Medicare and other insurance plans?

Answer: The use of transcutaneous electrical nerve stimulation (TENS) units for pain management is coded 64550 in CPT. This technique involves attachment of the device to the surface of the skin over the peripheral nerve to be stimulated. The patient uses it on a trial basis for pain control under close monitoring of the physician and/or physical therapist. The patient's response should be carefully documented, because medical necessity will be required for Medicare coverage after the first month. The TENS unit usually is provided by the physician for the assessment period. Because this is equipment used by the patient at home, it is covered under durable medical equipment (DME) guidelines.

Percutaneous electrical nerve stimulation (PENS) units involve stimulation of peripheral nerves by needle electrodes inserted through the skin. Code selections in this range include the following:

64553 — percutaneous implantation of neurostimulator electrodes; cranial nerve

64555 — peripheral nerve

64560 — autonomic nerve

64565 — neuromuscular

Medicare covers a PENS procedure only when performed by a physician or when it is "incident to" a physician's service. If pain is effectively controlled by percutaneous stimulation, the implantation of electrodes would be warranted.

Treatments would not be covered in a physician's office for Medicare patients, as it would be expected that a patient would have a stimulator implanted for home use.

The CPT codes for this service for 1999 are:

64573 — Incision for implantation of neurostimulator electrodes; cranial nerve

64575 — peripheral nerve

64577 — autonomic nerve

64580 — neuromuscular

Code 64585 is used for revision or removal of peripheral neurostimulator devices. Two additional codes in this section are for subcutaneous placement, revision, or removal of a peripheral neurostimulator pulse generator or receiver.

The devices are covered by Medicare, when medically necessary for pain control, under dur able medical equipment provisions.

Osteogenic stimulation

Electrical stimulation to enhance and augment bone repair can be invasive or noninvasive in nature. Invasive procedures provide electrical stimulation directly at the fracture site by percutaneously placed cathodes or by implantation of a coiled cathode wire in the site. The power pack required for the device is implanted into soft tissue near the fracture location and then subcutaneously connected to the cathode.

In a noninvasive procedure, opposing pads wired to an external power supply are placed over the patient's cast, creating an electromagnetic field between the pads at the fracture site.

The noninvasive procedure is covered by Medicare for the following conditions:

• nonunion of long bone fractures;

• failed fusion;

• congenital pseudoarthrosis;

• as an adjunct to spinal fusion surgery for patients at high risk for pseudoarthrosis due to failed spinal fusion at the same site or for those undergoing multiple-level fusion.

For all types of devices, nonunion is considered to exist only after six or more months have elapsed without healing of the fracture.

The invasive (implantable) stimulator is covered by Medicare for the following conditions:

• nonunion of long bone fractures;

• as an adjunct to spinal fusion surgery for patients at high risk of pseudoarthrosis due to previously failed spinal fusion at the same site or for those undergoing multiple-level fusion.

The CPT codes for osteogenic stimulation are:

20974 — electrical stimulation to aid bone healing; noninvasive (nonoperative)

20975 — invasive (operative)

NMES therapy

Neuromuscular electrical stimulation (NMES) is used to treat disuse atrophy. An NMES device transmits electrical impulses to the skin over selected muscle groups by way of electrodes. Medicare coverage of NMES is limited to treatment of disuse atrophy where the nerve supply to the muscle is intact, including brain, spinal cord, and peripheral nerves, and other non-neurological reasons for disuse are causing atrophy.

Examples include casting of a limb, contracture due to scarring of soft tissue such as burn patients may suffer, and hip replacement surgery until orthotic training has begun.

The CPT codes for neuromuscular electrical stimulation are found in the neurostimulator section of CPT. Electrodes placed over motor nerves stimulate muscles to prevent atrophy. In code 64565, the electrodes are placed at the neuromuscular junction to stimulate a specific area of muscle tissue.

The analysis of neurostimulators is reported from the medicine section of CPT. Codes in the range of 95970-95971 are assigned for this service.

This section of codes is all new for 1999 in CPT. It involves simple or complex electronic analysis of implanted neurostimulator pulse generator systems. The stimulation affects the pulse (amplitude, duration, frequency) to treat specific disorders such as Parkinson's disease. These codes are only used with implanted devices.

A simple stimulator affects three or fewer variables to include the pulse, electrode contacts, electrode selectability, output modulation, and cycling. A complex stimulator affects more than three of the variables. For complex procedures, when more than one hour is provided, there are codes for the additional time that are reported in addition to the primary procedure.